The present invention relates to improvements made to inflatable craft of the type comprising at least one inflatable sponson forming two substantially parallel members meeting towards the front to form a bow, and a transom linking said members and capable of receiving at least one motor or engine, each of said members comprising, at least in the substantially parallel portion thereof, several tubular compartments, each having a substantially circular cross-section, one of which is an upper compartment and one a lower compartment, placed longitudinally next to one another along a lower, circumferential area, facing the other member, of said upper compartment, which has a cross-section greater than that of said lower compartment, held against said upper compartment by a flexible side shell, made from cloth or fabric, which at least partially surrounds it and is firmly fixed to said upper compartment, said flexible shell being secured tangentially to said upper and lower compartments on the outer side of the member in question. In addition, a longitudinal keel is placed between a structural element forming a floor, which may be for example rigid, flexible or foldable, in the upper portion, which is held, at least in a transverse direction, along said two members, and a structural element forming a waterproof bottom, such as for example a waterproof bottom fabric, in the lower portion, which is connected to the peripheral edges of said floor, said keel tensioning said bottom, giving it the form of a V-shaped hull.